ISBN duplicate?

[Jazper]

I have an earlier, hardcover edition of this book Barrayar that apparently has the same ISBN as the one in GR. I've taken a so-so image of the cover, which is not already in the 'other editions' list and can't add it due to the conflict.

What should I have done? I added it without the ISBN since that appeared to be what I was suggested to do. Here's the one I added: Barrayar

I assume someone will have to combine it, if I didn't screw up somehow... I'm going through a library of thousands of books, some quite old, so I'd like to know the correct procedure as I expect I'll run into more.

Thx.

[rivka, Former Moderator]

Jazper wrote: "I added it without the ISBN since that appeared to be what I was suggested to do."

That's exactly right. I combined it with its fellows.